Quantized eigen beams for controlling antenna array elements in a wireless network

ABSTRACT

An apparatus of a wireless communication device operable to communicate channel state information in a wireless network can include memory and processing circuitry coupled to the memory. The processing circuitry is arranged to derive one or more principal eigen beams from received Orthogonal Frequency Division Multiple Access (OFDMA) signals, the one or more principal eigen beams having a rank greater than or equal to one. Quantized eigen beams may be derived from the one or more principal eigen beams. A bit pattern of the quantized eigen beams and at least one of a wideband channel quality indicator (CQI) or a subband CQI may be conditioned on the quantized eigen beams. Channel State Information Reference Signal (CSI-RS) may be encoded with the conditioned bit pattern for transmission to an Evolved Node-B (eNB) in the wireless network.

PRIORITY APPLICATION

This application is a continuation of U.S. application Ser. No.14/695,800, filed Apr. 24, 2015, now U.S. Pat. No. 9,397,736, whichclaims the benefit of priority to U.S. Provisional Patent ApplicationSer. No. 62/083,103, filed Nov. 21, 2014, which is incorporated hereinby reference in its entirety.

TECHNICAL FIELD

Embodiments described herein generally relate to communicating in awireless network.

BACKGROUND

A wireless device may include multiple antennas. For examples, theantennas may be arranged as antenna elements in an antenna array. Thereis ongoing effort to improve how the antenna elements are controlled.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of an antenna array having multiple antennaelements, in accordance with some embodiments.

FIG. 2 shows plots of cumulative distribution function (CDF) of thefirst 7 Givens rotation angles, in accordance with some embodiments.

FIG. 3 shows a plot of probability density function for γ_(4,0) for acomplex 8-by-1 beamforming vector in an independent and identicallydistributed (i.i.d.) channel, in accordance with some embodiments.

FIG. 4 shows a plot of probability density function for γ_(2,i) for acomplex 8-by-1 beamforming vector in an independent and identicallydistributed (i.i.d.) channel, in accordance with some embodiments.

FIG. 5 shows a plot of probability density function for γ_(1,j) for acomplex 8-by-1 beamforming vector in an independent and identicallydistributed (i.i.d.) channel, in accordance with some embodiments.

FIG. 6 shows an example system, in accordance with some embodiments.

FIG. 7 shows an example of computer circuitry that may be used tocommunicate channel state information in a cellular network, inaccordance with some embodiments.

FIG. 8 shows an example of a method that may be executed by computercircuitry, in accordance with some embodiments.

DETAILED DESCRIPTION

The following description and the drawings sufficiently illustratespecific embodiments to enable those skilled in the art to practicethem. Other embodiments may incorporate structural, logical, electrical,process, and other changes. Portions and features of some embodimentsmay be included in, or substituted for, those of other embodiments.Embodiments set forth in the claims encompass all available equivalentsof those claims.

In recent years, beamforming has become more common in user equipment(UE) devices, such as smart phones. For instance, a UE may usebeamforming techniques to transmit preferentially in a direction towardan enhanced Node B (eNB; also referred to as an evolved Node B).Similarly, the eNB may transmit preferentially in a direction toward aUE. In some examples, at least one of a UE and an eNB may also receivein a preferential direction, with increased sensitivity for signalsarriving from the preferential direction and reduced sensitivity forsignals arriving from directions away from the preferential direction.

Beamforming may be implemented on devices and systems that includemultiple antenna elements. For instance, a transmitter antenna array maytransmit a signal from multiple antenna elements, where each antennaelement may transmit the signal with its own specified phase delayand/or amplitude amplification. In some examples, the phase andamplitude factors may be controlled dynamically by the transmittingdevice, in order to maintain communication with a receiving device.Similarly, a receiving antenna array may receive a signal from multipleantenna elements, and may apply phase and amplitude factors to signalsreceived from the antenna elements to enhance sensitivity in aparticular direction. In some examples, the phase and amplitude factorsmay be controlled dynamically by the receiving device, in order tomaintain communication with a transmitting device.

In some examples, a UE may communicate channel state information in awireless network. The UE may include reception elements to receiveorthogonal frequency division multiple access (OFDMA) signals from aneNB. The UE may include derivation logic to derive one or more principaleigen beams from the received OFDMA signals. The principal eigen beamsmay have a rank greater than or equal to one. The UE may includequantization logic to form quantized eigen beams from the principaleigen beams. Such quantized eigen beams may determine how one layer istransmitted from multiple antenna ports. In some examples, thequantization logic may use Givens rotation to perform the quantization.The UE may include communication logic to communicate to the eNB a bitpattern of the quantized eigen beams and at least one of a widebandchannel quality indicator or a subband channel quality indicatorconditioned on the quantized eigen beams.

FIG. 1 shows an example of an antenna array 100 having multiple antennaelements, in accordance with some embodiments. Such an antenna array 100may be included in a UE or an eNB, or within other suitable devices. Insome examples, antenna elements 102 and 104 may be located at or nearthe same lateral location in the antenna array 100, but withorientations that are perpendicular to each other. In some examples, theantenna array 100 may include pairs of perpendicularly-oriented antennaelements positioned in a two-dimensional planar arrangement. In theexample of FIG. 1, antenna array 100 may be arranged as a rectangulargrid that includes M rows and N columns. Each location in the grid mayinclude a pair of antenna elements disposed within the plane of theantenna array 100, and inclined at +45 degrees and −45 degrees withrespect to the rows/columns. In the example of FIG. 1, if M is 8 and Nis 4, then the antenna array 100 includes 64 antenna elements. M and Nmay alternatively be any suitable positive integers.

A full-dimensional multiple-input multiple-output (FD-MIMO) system maybe described mathematically by Eq. (1):y=HPx+n  (1)

In Eq. (1), y is a receive vector having dimension N_(r)×1, where N_(r)is a number of receiving antennas. x is a transmit vector havingdimension N_(p)×1 where N_(p) is a number of layers. H is a channelmatrix having dimension N_(r)×N_(t), where N_(t) is a number oftransmitting antennas. P is a precoding matrix having dimensionN_(t)×N_(p). n is a noise vector having dimension N_(r)×1. During use ofa communication device, the device may form ongoing estimates of thechannel matrix H. The estimated values of H may be used to drive theantennas accordingly.

In some examples, such as devices that use the LTE Advanced (LTE-A)mobile communication standard up to Release 12, a Cell SpecificReference Signal (CRS) and/or a Channel State Information ReferenceSignal (CSI-RS) may be used to measure the channel state information.Release 12 of the LTE-A specification allows for only 1, 2, or 4 antennaports for CRS (often written as set {1, 2, 4}), and allows for only 1,2, 4, or 8 antenna ports for CSI-RS (often written as set {1, 2, 4, 8}).

In some examples, number of antenna ports supported by the mobilecommunication standard may be fewer than the number of antenna elementsin antenna array 100. For example, in the two-dimensional antenna array,100, the number of transmitting antennas N_(t) is given by N_(t)=2NM. Insome examples, the numerical value of N_(t) may be significantly largerthan 8. For example, for M=8 and N=4, the number of antennas isN_(t)=64, which is significantly larger than the 8 antenna ports allowedby the mobile communication standard.

One way for a device to use N_(t) antennas with only N_(c)∈{1,2,4,8}antenna ports is to virtualize the antennas into the antenna ports. Thisvirtualization is represented mathematically by Eq. (2):y=HP _(c) P _(d) x+n=ĤP _(d) x+n  (2)

Eq. (2) replaces the relatively large precoding matrix P with a productof two relatively small matrices, P_(c) and P_(d). Matrix P_(c) hasdimension N_(t)×N_(c), and matrix P_(d) has dimension N_(c)×N_(p). Insome examples, the number of antenna ports N_(c) (such as 1, 2, 4, or 8)may be significantly smaller than the number of transmitting antennasN_(t) (such as 64).

In Eq. (2), the channel matrix H is multiplied with matrix P_(d) to forman effective channel matrix, Ĥ=HP_(c), having a dimension N_(r)×N_(c).The number of transmitting antennas N_(t) may exceed the number ofantenna ports N_(c) by a factor of K, so that N_(t)=N_(c)K.

During the use of a communication device, the device may form ongoingestimates of the effective channel matrix {umlaut over (H)} over time.In some examples, it may be significantly easier to form estimates ofthe relatively small effective channel matrix {umlaut over (H)}, whichhas dimension N_(r)×N_(c), than to form estimates of the relativelylarge channel matrix H, which has dimension N_(r)×N_(t). Estimates ofthe effective channel matrix {umlaut over (H)} may provide the devicewith the information it uses to control its antennas.

In some examples, such as when an antenna virtualization matrix isupdated slowly over time, for instance, once every 200 ms, the antennavirtualization may be implemented in the analog domain. In otherexamples, such as when the antenna virtualization matrix varies as afunction of frequency, the antenna virtualization may be implemented inthe digital domain. In some examples, such as updated the antennavirtualization matrix slowly over time and applying the antennavirtualization matrix to the full system bandwidth, e.g. in the timescale of user arrival/departure or even slower, the antennavirtualization may be implemented in either the analog or digitaldomains.

Estimating of the effective channel matrix {umlaut over (H)} may dependon selecting matrices P_(c) and P_(d) with care. In some examples,matrix P_(c) may be designed semi-statically by the eNB. For someexamples, matrix P_(c) may remain effectively constant from estimationto estimation. In some examples, matrix P_(d) may be designed using acodebook to quantize the measured effective channel. Such a codebookdepends on the design of matrix P_(c).

In some examples, matrix P_(c) may subtract the major channel directionsof all the active UEs in one cell into No basic channel directions. Insome examples, each individual UE preferential channel direction becomesa combination of those N_(c) basic channel directions of one cell. Insome examples, such a matrix P_(c) may be used for both time-divisionduplexing (TDD) and frequency-division duplexing (FDD).

In some examples, matrix P_(c) may be formed with a principle of anideal subspace, where each antenna port virtualization vector may becalculated from an uplink composite channel covariance matrix.

For a given UE denoted by user k, an eNB may use uplink sounding toestimate an uplink channel matrix {tilde over (H)}_(k) for the user k.The eNB may use single value decomposition to calculate principal eigenbeams from an average channel covariance matrix of all UEs, as in Eq.(3):

$\begin{matrix}{{\frac{1}{K}{\sum{\overset{\sim}{H_{k}^{H}}\overset{\sim}{H_{k}}}}} = {USV}^{H}} & (3)\end{matrix}$

In Eq. (3), vector V is formed as V=[v₁ . . . v_(N) _(tx) ], where v_(c)is the c^(th) principal eigen beam. In some examples, the eNB may firstconstruct matrix P_(c) from the N_(c) largest principal eigen beams fromthe average channel covariance matrix. In some examples, the eNB mayselect the N_(c) largest principal eigen beams from the average channelcovariance matrix of Eq. (3). The eNB may normalize the energy of theeigen beams by dividing all the eigen beams by the square root of N_(c).The eNB may assemble the N_(c) largest principal eigen beams, allnormalized, to form matrix P_(c), as in Eq. (4):P _(c)=[v ₁ . . . v _(N) _(c) ]/√{square root over (N _(c))}  (4)

In some examples, once matrix P_(c) is obtained from Eq. (4), the eNB orUE may quantize the principal eigen beams for the effective channelmatrix, Ĥ=HP_(c), and arrive at matrix P_(d).

In some examples, the eNB or UE may use single value decomposition toextract the principal eigen beam of the effective channel matrix Ĥ, asin Eq. (5):Ĥ=ÛŜ{circumflex over (V)} ^(H)  (5)

In Eq. (5), rank r precoder {circumflex over (V)}_(r)=[{circumflex over(v)}₁ . . . {circumflex over (v)}_(r)]/√{square root over (r)} is formedfrom eigen beams v_(c) of the effective channel matrix Ĥ. Rank rsatisfies the condition of 1≤r≤min(N_(c),N_(r)).

In some examples, the eNB or UE may use Givens rotation to quantize theeigen beam based precoder. The following example uses rank r=2, althoughany suitable rank may be used, including 1, more than 1, 2, 3, 4, 5, 6,or more than 6.

Precoder matrix {circumflex over (V)}₂ of rank r=2 is given by Eq. (6):{circumflex over (V)} ₂=[{circumflex over (v)} ₁ {circumflex over (v)}₂]/√{square root over (2)}  (6)

In Eq. (6), each eigen beam {circumflex over (v)}₁, {circumflex over(v)}₂ is given by Eq. (7):

$\begin{matrix}{{\hat{v}}_{k} = \begin{bmatrix}\alpha_{0,k} \\\alpha_{1,k} \\\alpha_{2,k} \\\alpha_{3,k} \\\alpha_{4,k} \\\alpha_{5,k} \\\alpha_{6,k} \\\alpha_{7,k}\end{bmatrix}} & (7)\end{matrix}$

In Eq. (7), eigen beams {circumflex over (v)}₁, {circumflex over (v)}₂satisfy the condition of Eq. (8):

$\begin{matrix}{{{{\hat{v}}_{i}^{H}{\hat{v}}_{j}}} = \left\{ {{{\begin{matrix}{0,{i \neq j}} \\{1,{i = j}}\end{matrix}0} \leq i},{j \leq 1}} \right.} & (8)\end{matrix}$

Combining Eqs. (6) and (7), precoder matrix {circumflex over (V)}₂ isgiven by Eq. (9):

$\begin{matrix}{{\hat{V}}_{2} = {\begin{bmatrix}\alpha_{0,0} & \alpha_{0,1} \\\alpha_{1,0} & \alpha_{1,1} \\\alpha_{2,0} & \alpha_{2,1} \\\alpha_{3,0} & \alpha_{3,1} \\\alpha_{4,0} & \alpha_{4,1} \\\alpha_{5,0} & \alpha_{5,1} \\\alpha_{6,0} & \alpha_{6,1} \\\alpha_{7,0} & \alpha_{7,1}\end{bmatrix}/\sqrt{2}}} & (9)\end{matrix}$

In Eq. (9), the values in the precoder matrix {circumflex over (V)}₂ arecomplex numbers that each have an amplitude and phase given by Eq. (10):a _(i,j)=α_(i,j) e ^(jμi,j),0≤i≤7,0≤j≤1,0≤α_(i,j)≤1  (10)

Right-multiplying both sides of Eq. (9) with a diagonal matrix yieldsEq. (11):

$\begin{matrix}{{\hat{V}}_{2} = {{{\hat{V}}_{2}\begin{bmatrix}e^{{- j}\;\mu_{7,0}} & 0 \\0 & e^{{- j}\;\mu_{7,1}}\end{bmatrix}} = \begin{bmatrix}b_{0,0} & b_{0,1} \\b_{1,0} & b_{1,1} \\b_{2,0} & b_{2,1} \\b_{3,0} & b_{3,1} \\b_{4,0} & b_{4,1} \\b_{5,0} & b_{5,1} \\b_{6,0} & b_{6,1} \\\alpha_{7,0} & \alpha_{7,1}\end{bmatrix}}} & (11)\end{matrix}$

In Eq. (11), values b_(i,j) are given by Eq. (12):b _(i,j) =a _(i,j) e ^(−jμ7,j)=α_(i,j) e ^(jδi,j),0≤i≤6,0≤j≤1  (12)

The right-multiplication above may change the last element of bothcolumns to a non-negative real number without changing the orthogonalitybetween two columns.

Left-multiplying both sides of Eq. (11) with a square diagonal matrixmay change the elements of the first column from complex number tonon-negative real number. The square diagonal matrix may be expandedfrom one vector as Eq. (13):D ₀=diag([e ^(jδ) ^(0,0) e ^(jδ) ^(1,0) e ^(jδ) ^(2,0) e ^(jδ) ^(3,0) e^(jδ) ^(4,0) e ^(jδ) ^(5,0) e ^(jδ) ^(6,0) 1])  (13)

After the left-multiplication above, the precoder matrix {circumflexover (V)}₂ may be represented as Eq. (14):

$\begin{matrix}{{\hat{V}}_{2} = {{D_{0}{\hat{V}}_{2}} = \begin{bmatrix}\alpha_{0,0} & c_{0,1} \\\alpha_{1,0} & c_{1,1} \\\alpha_{2,0} & c_{2,1} \\\alpha_{3,0} & c_{3,1} \\\alpha_{4,0} & c_{4,1} \\\alpha_{5,0} & c_{5,1} \\\alpha_{6,0} & c_{6,1} \\\alpha_{7,0} & \alpha_{7,1}\end{bmatrix}}} & (14)\end{matrix}$

Rotating the precoder matrix {circumflex over (V)}₂, via a Givensrotation, may the place the first column in the form of a unit vector.Applying a Givens rotation involves multiplying the precoder matrix{circumflex over (V)}₂ by a Givens rotation matrix, as in Eq. (15):

$\begin{matrix}{G_{k} = \begin{bmatrix}{\cos\left( \varnothing_{k} \right)} & {\sin\left( \varnothing_{k} \right)} \\{- {\sin\left( \varnothing_{k} \right)}} & {\cos\left( \varnothing_{k} \right)}\end{bmatrix}} & (15)\end{matrix}$

In Eq. (15), angle Ø_(k) is given by Eq. (16):Ø_(k)=α cos(α_(0,0)/√{square root over (α_(0,0) ²+α_(k,0) ²)})  (16)

In some examples, parameter α_(0,0) may vary with each rotation. Therotation matrix affects a submatrix of precoder matrix {circumflex over(V)}₂ at row 0 and k+1.

After seven Givens rotation matrices are applied, the precoder matrix{circumflex over (V)}₂ is given by Eq. (17):

$\begin{matrix}{{\hat{V}}_{2} = \begin{bmatrix}1 & 0 \\0 & 1 \\0 & d_{2,1} \\0 & d_{3,1} \\0 & d_{4,1} \\0 & d_{5,1} \\0 & d_{6,1} \\0 & d_{7,1}\end{bmatrix}} & (17)\end{matrix}$

where d_(i,1)=α_(i,1)e^(jγi),2≤i≤7. Repeating Eqs. (13) through (17) forthe last six elements of the second column reduce the precoder matrix{circumflex over (V)}₂ to Eq. (18):

$\begin{matrix}{{\hat{V}}_{2} = \begin{bmatrix}1 & 0 \\0 & 1 \\0 & 0 \\0 & 0 \\0 & 0 \\0 & 0 \\0 & 0 \\0 & 0\end{bmatrix}} & (18)\end{matrix}$

In some examples, applying Eqs. (13) to (18) as discussed above mayquantize the rank r=2 precoder matrix {circumflex over (V)}₂ into 26values of phase Ø. In some examples, the first half (e.g., 13) of thephases Ø may be used in the square diagonal matrix D₀ to rotate eachelement from complex number to non-negative real number. In someexamples, the first half of the phases Ø may be evenly distributed in arange between 0 and 2*pi. In some examples, each phase Ø may use N_(P)bits to quantize, as in Eq. (19):

$\begin{matrix}{{\hat{\varphi}}_{m} = {\left( {\left\lfloor {\varphi_{m}/\left( {2{\pi/2^{Np}}} \right)} \right\rfloor + 0.5} \right)\frac{2\pi}{2^{Np}}}} & (19)\end{matrix}$

In some examples, the second half (e.g., remaining 13) of the phases Ømay be the rotation angles used in the Givens rotation matrix G_(k) fromEq. (15). The first 7 of these phases Ø may be used for the first columnof the precoder matrix {circumflex over (V)}₂ and the remaining 6 may beused for the second column of the precoder matrix {circumflex over(V)}₂.

FIG. 2 shows plots of cumulative distribution function (CDF) of thefirst 7 Givens rotation angles, in accordance with some embodiments. Thevalid range of Givens rotation angles is between 0 and pi/2. FIG. 2shows that as the precoder is rotated iteratively, the distribution ofthe Givens angle becomes non-evenly distributed and more concentrated tosmall values. In some examples, this small-value concentration may beused to either the quantization accuracy. For example, even quantizationmay be applied to Eq. (18) in a reduced angular range extending from 0to pi/2. In some examples, this small-value concentration may be used toreduce the quantization overhead. For example, the CDF curves in FIG. 2may quantize each phase into N_(s) bits, as in Eq. (20):

$\begin{matrix}{{\hat{\varphi}}_{m} = {F^{- 1}\left( {\left( {\left\lfloor {{F\left( \varphi_{m} \right)}/\left( {1/2^{N_{s}}} \right)} \right\rfloor + 0.5} \right)\frac{1}{2^{N_{s}}}} \right)}} & (20)\end{matrix}$

In FIG. 2 and Eq. (20), the cumulative distribution function (CDF) isgiven by Eq. (21):F(φ_(m))=P{x<φ _(m)}  (21)

The Appendix provides numerical values for each curve shown in FIG. 2.

With the 26 quantized angles, the eNB may fully recover a rank twoprecoder. In some examples, the quantization technique discussed abovemay be inserted in section 7.2.4 of specification document TS36.213(E-UTRA) physical layer procedures.

As an alternative to the Givens rotation technique discussed above, asecond quantization technique is discussed presently. This secondquantization technique uses an 8-by-2 unitary matrix as an example. Thissecond quantization technique repeats the notations and operations ofEqs. (9) through (14). The complex, unitary, beamforming matrix underquantization is first converted to a non-negative matrix using Eqs. (9)through (14).

The first column of a precoder matrix {circumflex over (V)}₂ of rankr==2 is given by Eq. (22):

$\begin{matrix}{v_{0} = \begin{bmatrix}\alpha_{0,0} \\\alpha_{1,0} \\\alpha_{2,0} \\\alpha_{3,0} \\\alpha_{4,0} \\\alpha_{5,0} \\\alpha_{6,0} \\\alpha_{7,0}\end{bmatrix}} & (22)\end{matrix}$

The column may be divided into two groups with the same number or aboutthe same number of entries, as in Eqs. (23) and (24):

$\begin{matrix}{a_{4,0} = \left\lfloor \begin{matrix}\alpha_{0,0} \\\alpha_{1,0} \\\alpha_{2,0} \\\alpha_{3,0}\end{matrix} \right\rfloor} & (23) \\{b_{4,0} = \left\lfloor \begin{matrix}\alpha_{4,0} \\\alpha_{5,0} \\\alpha_{6,0} \\\alpha_{7,0}\end{matrix} \right\rfloor} & (24)\end{matrix}$

Note that for an even number of rows, the two groups can have the samenumber of entries. For an odd number of rows, one group may have onemore entry than the other group. Ratio γ may be defined between groups aand b, as in Eq. (25):

$\begin{matrix}{\gamma = \frac{{f(a)} - {f(b)}}{{f(a)} + {f(b)}}} & (25)\end{matrix}$

In Eq. (25), function ƒ(x) may represent the magnitude of the vector orscalar x and may be defined by Eq. (26) using square norm or by Eq. (27)for absolute value norm:ƒ(x)=|x| ²  (26)ƒ(x)=|x ₀ |+|x ₁ |+ . . . +|x _(N)|  (27)

From ratio γ, the ratio between ƒ(a) and ƒ(b) may be computed as in Eq.(28):

$\begin{matrix}{\frac{f(a)}{f(b)} = \frac{1 + \gamma}{1 - \gamma}} & (28)\end{matrix}$

Using the square of vector norm |x|² for Eq. (23) and (24) gives Eq.(29):

$\begin{matrix}{\gamma_{4,0} = \frac{{a_{4,0}}^{2} - {b_{4,0}}^{2}}{{a_{4,0}}^{2} + {b_{4,0}}^{2}}} & (29)\end{matrix}$

Similarly, we may recursively divide a_(4,0) (and b_(4,0)) into twosubgroups and define the ratio between the two subgroups as Eqs. (30)through (35):

$\begin{matrix}{{a_{2,0} = \begin{bmatrix}\alpha_{0,0} \\\alpha_{1,0}\end{bmatrix}},{b_{2,0} = \begin{bmatrix}\alpha_{2,0} \\\alpha_{3,0}\end{bmatrix}},\mspace{11mu}{{{and}\mspace{14mu}\gamma_{2,0}} = \frac{{a_{2,0}}^{2} - {b_{2,0}}^{2}}{{a_{2,0}}^{2} + {b_{2,0}}^{2}}}} & (30) \\{{a_{2,1} = \begin{bmatrix}\alpha_{4,0} \\\alpha_{5,0}\end{bmatrix}},{b_{2,1} = \begin{bmatrix}\alpha_{6,0} \\\alpha_{7,0}\end{bmatrix}},\mspace{11mu}{{{and}\mspace{14mu}\gamma_{2,1}} = \frac{{a_{2,1}}^{2} - {b_{2,1}}^{2}}{{a_{2,1}}^{2} + {b_{2,1}}^{2}}}} & (31) \\{{a_{1,0} = \alpha_{0,0}},{b_{1,0} = \alpha_{1,0}},\mspace{11mu}{{{and}\mspace{14mu}\gamma_{1,0}} = \frac{{a_{1,0}}^{2} - {b_{1,0}}^{2}}{{a_{1,0}}^{2} + {b_{1,0}}^{2}}}} & (32) \\{{a_{1,1} = \alpha_{2,0}},{b_{1,1} = \alpha_{3,0}},\mspace{11mu}{{{and}\mspace{14mu}\gamma_{1,1}} = \frac{{a_{1,1}}^{2} - {b_{1,1}}^{2}}{{a_{1,1}}^{2} + {b_{1,1}}^{2}}}} & (33) \\{{a_{1,2} = \alpha_{4,0}},{b_{1,2} = \alpha_{5,0}},\mspace{11mu}{{{and}\mspace{14mu}\gamma_{1,2}} = \frac{{a_{1,2}}^{2} - {b_{1,2}}^{2}}{{a_{1,2}}^{2} + {b_{1,2}}^{2}}}} & (34) \\{{a_{1,3} = \alpha_{6,0}},{b_{1,3} = \alpha_{7,0}},\mspace{11mu}{{{and}\mspace{14mu}\gamma_{1,3}} = \frac{{a_{1,3}}^{2} - {b_{1,3}}^{2}}{{a_{1,3}}^{2} + {b_{1,3}}^{2}}}} & (35)\end{matrix}$

FIG. 3 shows a plot of probability density function for γ_(4,0) for acomplex 8-by-1 beamforming vector in an independent and identicallydistributed (i.i.d.) channel, in accordance with some embodiments.

FIG. 4 shows a plot of probability density function for γ_(2,i) for acomplex 8-by-1 beamforming vector in an independent and identicallydistributed (i.i.d.) channel, in accordance with some embodiments. InFIG. 4, i=0, 1.

FIG. 5 shows a plot of probability density function for γ_(1,j) for acomplex 8-by-1 beamforming vector in an independent and identicallydistributed (i.i.d.) channel, in accordance with some embodiments. InFIG. 5, j=0, 1, 2, 3.

The ratios γ, such as those shown in FIGS. 3-5, may be quantized. Themagnitudes of the beamforming vector may be reconstructed from thequantized ratios as in Eqs. (36) through (43):â _(0,0)=ƒ⁻¹((1+{circumflex over (γ)}_(4,0))(1+{circumflex over(γ)}_(2,0))(1+{circumflex over (γ)}_(1,0)))  (36)â _(1,0)=ƒ⁻¹((1+{circumflex over (γ)}_(4,0))(1+{circumflex over(γ)}_(2,0))(1−{circumflex over (γ)}_(1,0)))  (37)â _(2,0)=ƒ⁻¹((1+{circumflex over (γ)}_(4,0))(1+{circumflex over(γ)}_(2,0))(1+{circumflex over (γ)}_(1,1)))  (38)â _(3,0)=ƒ⁻¹((1+{circumflex over (γ)}_(4,0))(1−{circumflex over(γ)}_(2,0))(1−{circumflex over (γ)}_(1,1)))  (39)â _(4,0)=ƒ⁻¹((1−{circumflex over (γ)}_(4,0))(1+{circumflex over(γ)}_(2,1))(1+{circumflex over (γ)}_(1,2)))  (40)â _(5,0)=ƒ⁻¹((1−{circumflex over (γ)}_(4,0))(1+{circumflex over(γ)}_(2,1))(1−{circumflex over (γ)}_(1,2)))  (41)â _(6,0)=ƒ⁻¹((1−{circumflex over (γ)}_(4,0))(1−{circumflex over(γ)}_(2,1))(1+{circumflex over (γ)}_(1,3)))  (42)â _(7,0)=ƒ⁻¹((1−{circumflex over (γ)}_(4,0))(1−{circumflex over(γ)}_(2,1))(1−{circumflex over (γ)}_(1,3)))  (43)

For ƒ(x)=∥x∥², ƒ⁻¹(x)=√{square root over (x)}. The reconstructedbeamforming vector may have an ambiguity about the column phase and themagnitude, which does not affect the beamforming performance. After thefirst column is quantized, the quantized column may be used to rotatethe second column in an 8-by-2 beamforming matrix such that a 7-by-1vector is obtained for the quantization of the second column. Thequantization of the 7-by-1 vector may be quantized in a manner similarto the one for the 8-by-1 vector, by dividing the entries into twogroups recursively and quantize the ratio between the two groups.

Consider the following example. For this example, an eNB antenna arrayhas 64 antenna elements. A 64-by-8 matrix may virtualize 64 antennaelements to 8 antenna ports. If the quantized rank one eigen beam is[0.1, 0.2, 0.3j, 0, 0, 0, 0, 0]^(T), then a particular data layer may betransmitted from the first three antenna ports with weight 0.1, 0.2, and0.3j, respectively. A CSI-RS may be sent from the eNB. In this example,the CSI-RS has 8 ports. The UE sends CSI back to the eNB via the uplinkchannels PUCCH (Physical Uplink Control Channel) or PUSCH (PhysicalUplink Shared Channel). This is but one example; other suitable examplesmay also be used.

Embodiments described herein may be implemented into a system using anysuitable configured hardware and/or software. FIG. 6 shows, for oneembodiment, an example system 600 that includes transceiver circuitry602, baseband circuitry 604, processing circuitry 606, memory/storage608, display 610, camera 612, sensor 614, and input/output (I/O)interface 616, coupled with each other at least as shown.

The processing circuitry 606 may include circuitry such as, but notlimited to, one or more single-core or multi-core processors. Theprocessor(s) may include any combination of general-purpose processorsand dedicated processors (e.g., graphics processors, applicationprocessors, etc.). The processors may be coupled with memory/storage 608and arranged to execute instructions stored in the memory/storage 608 toenable various applications and/or operating systems running on thesystem 600.

The baseband circuitry 604 may include circuitry such as, but notlimited to, one or more single-core or multi-core processors. Theprocessor(s) may include a baseband processor. The baseband circuitry604 may handle various radio control functions that allows forcommunication with one or more radio networks via the transceivercircuitry 602. The radio control functions may include, but are notlimited to, signal modulation, encoding, decoding, radio frequencyshifting, etc. In some embodiments, the baseband circuitry 604 mayprovide for communication compatible with one or more radiotechnologies. For example, in some embodiments, the baseband circuitry604 may support communication with an evolved universal terrestrialradio access network (EUTRAN) and/or other wireless metropolitan areanetworks (WMAN), a wireless local area network (WLAN), a wirelesspersonal area network (WP AN). Embodiments in which the basebandcircuitry 604 is arranged to support radio communications of more thanone wireless protocol may be referred to as multi-mode basebandcircuitry.

In various embodiments, baseband circuitry 604 may include circuitry tooperate with signals that are not strictly considered as being in abaseband frequency. For example, in some embodiments, baseband circuitry604 may include circuitry to operate with signals having an intermediatefrequency, which is between a baseband frequency and a radio frequency.

Transceiver circuitry 602 may enable communication with wirelessnetworks using modulated electromagnetic radiation through a non-solidmedium. In various embodiments, the transceiver circuitry 602 mayinclude switches, filters, amplifiers, etc. to facilitate thecommunication with the wireless network.

In various embodiments, transceiver circuitry 602 may include circuitryto operate with signals that are not strictly considered as being in aradio frequency. For example, in some embodiments, transceiver circuitry602 may include circuitry to operate with signals having an intermediatefrequency, which is between a baseband frequency and a radio frequency.

In various embodiments, the derivation logic, quantization logic, andcommunication logic discussed herein with respect to the UE (and shownin FIG. 7 below) may be embodied in whole or in part in one or more ofthe transceiver circuitry 602, the baseband circuitry 604, and/or theprocessing circuitry 606. As used herein, the term circuitry may referto, be part of, or include an Application Specific Integrated Circuit(ASIC), an electronic circuit, a processor (shared, dedicated, orgroup), and/or memory (shared, dedicated, or group) that execute one ormore software or firmware programs, a combinational logic circuit,and/or other suitable hardware components that provide the describedfunctionality. In some embodiments, the electronic device circuitry maybe implemented in, or functions associated with the circuitry may beimplemented by, one or more software or firmware modules.

In some embodiments, some or all of the constituent components of thebaseband circuitry 604, the processing circuitry 606, and/or thememory/storage 608 may be implemented together on a system on a chip(SOC).

Memory/storage 608 may be used to load and store data and/orinstructions, for example, for system 600. Memory/storage 608 for oneembodiment may include any combination of suitable volatile memory(e.g., dynamic random access memory (DRAM)) and/or non-volatile memory(e.g., Flash memory).

In various embodiments, the I/O interface 616 may include one or moreuser interfaces designed to enable user interaction with the system 600and/or peripheral component interfaces designed to enable peripheralcomponent interaction with the system 600. User interfaces may include,but are not limited to a physical keyboard or keypad, a touchpad, aspeaker, a microphone, etc. Peripheral component interfaces may include,but are not limited to, a nonvolatile memory port, a universal serialbus (USB) port, an audio jack, and a power supply interface.

In various embodiments sensor 614 may include one or more sensingdevices to determine environmental conditions and/or locationinformation related to the system 600. In some embodiments, the sensors614 may include, but are not limited to, a gyro sensor, anaccelerometer, a proximity sensor, an ambient light sensor, and apositioning unit. The positioning unit may also be part of, or interactwith, the baseband circuitry and/or transceiver circuitry to communicatewith components of a positioning network, e.g., a global positioningsystem (GPS) satellite.

In various embodiments, the display 610 may include a display (e.g., aliquid crystal display, a touch screen display, etc.).

In various embodiments, the system 600 may be a mobile computing devicesuch as, but not limited to, a laptop computing device, a tabletcomputing device, a netbook, an ultrabook, a smartphone, etc. In variousembodiments, system may have more or fewer components, and/or differentarchitectures.

FIG. 7 shows an example of computer circuitry 700, such as in userequipment, that may be used to communicate channel state information ina cellular network. In some examples, the computer circuitry 700 mayinclude derivation logic 702 and quantization logic 704 coupled tocommunication logic 706. The computer circuitry 700 may be coupled withone or more plurality of antenna elements 708A-D of one or more antennasor one or more wired transmission/reception elements 710. The computercircuitry 700 and/or the components of the computer circuitry 700 may bearranged to perform operations similar to those described elsewhere inthis disclosure.

Specifically, the wired transmission/reception elements 710 may bearranged to receive a plurality of orthogonal frequency divisionmultiple access (OFDMA) signals. The derivation logic 702 may bearranged to derive one or more principal eigen beams through measurementof the plurality of OFDMA signals. The quantization logic 704 may bearranged to quantize principal eigen beams having a rank greater than orequal to one. The communication logic 706 may be arranged tocommunicate, to an eNB, a bit pattern of the recommended eigen beams andthe wideband and/or subband channel quality indicator (CQI) conditionedon the quantized eigen beam. The wired transmission/reception elements710 may be further arranged to receive data sent from the eNB's antennaelements using the precoder calculated from its principal eigen beams.

As used herein, the term logic may refer to, be part of, or includecircuitry, such as an Application Specific Integrated Circuit (ASIC), anelectronic circuit, a processor (shared, dedicated, or group), and/ormemory (shared, dedicated, or group) that execute one or more softwareor firmware programs, a combinational logic circuit, and/or othersuitable hardware components that provide the described functionality.In some embodiments, the electronic device circuitry may be implementedin, or functions associated with the circuitry may be implemented by,one or more software or firmware modules. Thus, as used herein logic mayalso include software and/or firmware modules which may be operated onmy one or more computer processors of the apparatus to provide thedescribed functionality.

FIG. 8 shows an example of a method 800 that may be executed by computercircuitry, such as 602, 604, 606 (FIG. 6), and/or 700 (FIG. 7), inaccordance with some embodiments.

At operation 802, transceiver circuitry may receive, at the UE, from aneNB, a plurality of orthogonal frequency division multiple access(OFDMA) signals.

At operation 804, processing circuitry may derive one or more principaleigen beams from the received OFDMA signals. The principal eigen beamsmay have a rank greater than or equal to one.

At operation 806, the processing circuitry may derive quantized eigenbeams from the principal eigen beams.

At operation 808, the transceiver circuitry may communicate to the eNB,via a Channel State Information Reference Signal (CSI-RS), a bit patternof the quantized eigen beams and at least one of a wideband channelquality indicator (CQI) or a subband CQI conditioned on the quantizedeigen beams.

Additional examples of the presently described method, system, anddevice embodiments include the following, non-limiting configurations.Each of the following non-limiting examples may stand on its own, or maybe combined in any permutation or combination with any one or more ofthe other examples provided below or throughout the present disclosure.

Example 1 is a user equipment (UE) operable to communicate channel stateinformation in a wireless network, the UE comprising: transceivercircuitry arranged to receive, at the UE, from an Enhanced node B (eNB),a plurality of orthogonal frequency division multiple access (OFDMA)signals: processing circuitry arranged to derive one or more principaleigen beams from the received OFDMA signals, the principal eigen beamshaving a rank greater than or equal to one, the processing circuitryarranged to derive quantized eigen beams from the principal eigen beams,the processing circuitry further arranged to select, in response to thequantized eigen beams, a subset of available antenna ports on the eNBfor receiving from the eNB and transmitting to the eNB: and thetransceiver circuitry arranged to communicate to the eNB, via a ChannelState Information Reference Signal (CSI-RS), a bit pattern of thequantized eigen beams and at least one of a wideband channel qualityindicator (CQI) or a subband CQI conditioned on the quantized eigenbeams.

In Example 2, the subject matter of Example 1 may optionally includewherein the transceiver circuitry is further arranged to select, inresponse to the quantized eigen beams, a subset of available antennaports on the eNB for receiving from the eNB and transmitting to the eNB.

In Example 3, the subject matter of any one of Examples 1-2 mayoptionally include wherein the processing circuitry is further arrangedto calculate, in response to the quantized eigen beams, a plurality ofphase values and a plurality of amplitude values, each amplitude andphase value corresponding to a respective antenna port in the subset ofavailable antenna ports, each amplitude value corresponding to a signalamplification factor, each phase value corresponding to a signal phasedelay.

In Example 4, the subject matter of any one of Examples 1-3 mayoptionally include wherein the processing circuitry uses a Givensrotation to quantize antenna ports numbering Nc for the principal eigenbeams.

In Example 5, the subject matter of any one of Examples 1-4 mayoptionally include wherein the processing circuitry further quantizes aprecoder of rank r into phases numbering 2*Σ_(k=0) ^(r)(Nc−k−1) where Ncis a number of antenna ports on the UE.

In Example 6, the subject matter of any one of Examples 1-5 mayoptionally include wherein the processing circuitry evenly quantizes afirst half of the phases to have Np bits per phase, where Np is a numberof layers; and wherein the processing circuitry unevenly quantizes asecond half of the phases to have Ns bits per phase.

In Example 7, the subject matter of any one of Examples 1-6 mayoptionally include wherein the processing circuitry uses the first halfof the phases to rotate each element of the precoder from a complexnumber to a nonnegative real number; and wherein the processingcircuitry uses the second half of the phases to rotate the precoder toan identity matrix.

In Example 8, the subject matter of any one of Examples 1-7 mayoptionally include wherein the processing circuitry quantizes eachphase, of the first half of the phases, evenly in the range between 0and 2*pi; and wherein the processing circuitry quantizes each phase, ofthe first half of the phases, according to the equationD ₀=diag([e ^(jδ) ^(0,0) e ^(jδ) ^(1,0) e ^(jδ) ^(2,0) e ^(jδ) ^(3,0) e^(jδ) ^(4,0) e ^(jδ) ^(5,0) e ^(jδ) ^(6,0) 1]).

In Example 9, the subject matter of any one of Examples 1-8 mayoptionally include wherein the processing circuitry quantizes eachphase, of the second half of the phases, in the range between 0 and 2*piusing a cumulative distribution function (CDF).

In Example 10, the subject matter of any one of Examples 1-9 mayoptionally include wherein the processing circuitry maps each phase, ofthe second half of the phases, to the CDF; wherein the processingcircuitry evenly quantizes a phase probability in a range between 0 and1 to form a quantized probability; wherein the processing circuitry mapsthe quantized probability using an inverse of the CDF to a quantizedphase; and wherein the processing circuitry sequentially quantizesphases of each column of the CDF.

In Example 11, the subject matter of any one of Examples 1-10 mayoptionally include wherein the processing circuitry further quantizes aprecoder of rank r into phases and ratios, the phases and ratios bothnumbering 2*Σ_(k=0) ^(r)(Nc−k−1), where Nc is a number of antenna portson the UE.

In Example 12, the subject matter of any one of Examples 1-11 mayoptionally include wherein the processing circuitry further quantizesthe ratios according to the equations

${a_{2,0} = \begin{bmatrix}\alpha_{0,0} \\\alpha_{1,0}\end{bmatrix}},{b_{2,0} = \begin{bmatrix}\alpha_{2,0} \\\alpha_{3,0}\end{bmatrix}},\mspace{11mu}{{{{and}\mspace{14mu}\gamma_{2,0}} = \frac{{a_{2,0}}^{2} - {b_{2,0}}^{2}}{{a_{2,0}}^{2} + {b_{2,0}}^{2}}};}$${a_{2,1} = \begin{bmatrix}\alpha_{4,0} \\\alpha_{5,0}\end{bmatrix}},{b_{2,1} = \begin{bmatrix}\alpha_{6,0} \\\alpha_{7,0}\end{bmatrix}},\mspace{11mu}{{{{and}\mspace{14mu}\gamma_{2,1}} = \frac{{a_{2,1}}^{2} - {b_{2,1}}^{2}}{{a_{2,1}}^{2} + {b_{2,1}}^{2}}};}$${a_{1,0} = \alpha_{0,0}},{b_{1,0} = \alpha_{1,0}},\mspace{11mu}{{{{and}\mspace{14mu}\gamma_{1,0}} = \frac{{a_{1,0}}^{2} - {b_{1,0}}^{2}}{{a_{1,0}}^{2} + {b_{1,0}}^{2}}};}$${a_{1,1} = \alpha_{2,0}},{b_{1,1} = \alpha_{3,0}},\mspace{11mu}{{{{and}\mspace{14mu}\gamma_{1,1}} = \frac{{a_{1,1}}^{2} - {b_{1,1}}^{2}}{{a_{1,1}}^{2} + {b_{1,1}}^{2}}};}$${a_{1,2} = \alpha_{4,0}},{b_{1,2} = \alpha_{5,0}},\mspace{11mu}{{{{and}\mspace{14mu}\gamma_{1,2}} = \frac{{a_{1,2}}^{2} - {b_{1,2}}^{2}}{{a_{1,2}}^{2} + {b_{1,2}}^{2}}};\mspace{11mu}{and}}$${a_{1,3} = \alpha_{6,0}},{b_{1,3} = \alpha_{7,0}},\mspace{11mu}{{{and}\mspace{14mu}\gamma_{1,3}} = {\frac{{a_{1,3}}^{2} - {b_{1,3}}^{2}}{{a_{1,3}}^{2} + {b_{1,3}}^{2}}.}}$

In Example 13, the subject matter of any one of Examples 1-12 mayoptionally include wherein the transceiver circuitry further receivesdata sent from antenna elements of the eNB using a precoder calculatedfrom the principal eigen beams; and wherein and received OFDMA signal istransmitted with an independent beamforming pattern from an antennaarray of the eNB.

In Example 14, the subject matter of any one of Examples 1-13 mayoptionally include wherein the transceiver circuitry is coupled to atleast one antenna.

Example 15 is a method for communicating channel state information froma user equipment (UE) to an Enhanced node B (eNB) in a wireless network,the method comprising: deriving, at the UE, one or more principal eigenbeams from received orthogonal frequency division multiple access(OFDMA) signals, the principal eigen beams having a rank greater than orequal to one; deriving, at the UE, quantized eigen beams from theprincipal eigen beams; and selecting, at the UE, in response to thequantized eigen beams, a subset of available antenna ports on the eNBfor receiving from the eNB and transmitting to the eNB; and wherein theUE uses a Givens rotation to quantize antenna ports numbering Nc for theprincipal eigen beams.

In Example 16, the subject matter of Example 15 may optionally includecommunicating, from the UE to the eNB, via a Channel State InformationReference Signal (CSI-RS), a bit pattern of the quantized eigen beamsand at least one of a wideband channel quality indicator (CQI) or asubband CQI conditioned on the quantized eigen beams.

In Example 17, the subject matter of any one of Examples 15-16 mayoptionally include further comprising, at the UE: quantizing a precoderof rank r into phases numbering 2*Σ_(k=0) ^(r) (Nc−k−1), where Nc is anumber of antenna ports on the UE; wherein the UE evenly quantizes afirst half of the phases to have Np bits per phase, where Np is a numberof layers; and wherein the UE unevenly quantizes a second half of thephases to have Ns bits per phase.

In Example 18, the subject matter of any one of Examples 15-17 mayoptionally include wherein the UE evenly quantizes a first half of thephases to have Np bits per phase, where Np is a number of layers;wherein the UE unevenly quantizes a second half of the phases to have Nsbits per phase; wherein the UE uses the first half of the phases torotate each element of the precoder from a complex number to anonnegative real number; and wherein the UE uses the second half of thephases to rotate the precoder to an identity matrix.

Example 19 is a non-transitory computer-readable medium containinginstructions which, when executed, perform operations to communicatechannel state information from a user equipment (UE) to an Enhanced nodeB (eNB) in a wireless network, the operations to arrange the UE to:receive from the eNB a plurality of orthogonal frequency divisionmultiple access (OFDMA) signals; derive one or more principal eigenbeams from the received OFDMA signals, the principal eigen beams havinga rank greater than or equal to one; derive quantized eigen beams fromthe principal eigen beams; select, in response to the quantized eigenbeams, a subset of available antenna ports on the eNB for receiving fromthe eNB and transmitting to the eNB; and communicate, from the UE to theeNB, via a Channel State Information Reference Signal (CSI-RS), a bitpattern of the quantized eigen beams and at least one of a widebandchannel quality indicator (CQI) or a subband CQI conditioned on thequantized eigen beams; wherein the operations further arrange the UE toquantize a precoder of rank r into phases and ratios, the phases andratios both numbering 2*Σ_(k=0) ^(r) (Nc−k−1), where Nc is a number ofantenna ports on the UE.

In Example 20, the subject matter of Example 19 may optionally includewherein the operations further arrange the UE to receive data sent fromantenna elements of the eNB using a precoder calculated from theprincipal eigen beams; and wherein each received OFDMA signal istransmitted with an independent beamforming pattern from an antennaarray of the eNB.

APPENDIX

The following are vectors that may be used to reproduce the plots shownin FIG. 2. In the notation below, x_1 are the x-values of data points onthe curve for angle 1, y_1 are the y-values of data points on the curvefor angle 1, x_2 are the x-values for data points on the curve for angle2, and so forth.

double x_1[101]={0.0100, 0.0207, 0.0483, 0.0698, 0.0805, 0.0989, 0.1174,0.1388, 0.1557, 0.1664, 0.1910, 0.1971, 0.2171, 0.2278, 0.2355, 0.2447,0.2493, 0.2615, 0.2815, 0.2907, 0.3014, 0.3152, 0.3229, 0.3321, 0.3398,0.3567, 0.3659, 0.3812, 0.3919, 0.4180, 0.4334, 0.4395, 0.4487, 0.4717,0.4870, 0.5008, 0.5147, 0.5300, 0.5453, 0.5775, 0.5929, 0.6036, 0.6159,0.6481, 0.6680, 0.6926, 0.7049, 0.7202, 0.7417, 0.7570, 0.7724, 0.7938,0.8122, 0.8291, 0.8460, 0.8828, 0.8935, 0.9058, 0.9227, 0.9426, 0.9518,0.9702, 0.9887, 1.0147, 1.0485, 1.0638, 1.0700, 1.0884, 1.1006, 1.1221,1.1344, 1.1466, 1.1497, 1.1651, 1.1789, 1.1911, 1.2049, 1.2080, 1.2295,1.2387, 1.2540, 1.2709, 1.2862, 1.2939, 1.3154, 1.3353, 1.3415, 1.3553,1.3737, 1.3814, 1.4059, 1.4120, 1.4166, 1.4258, 1.4412, 1.4534, 1.4627,1.4703, 1.4979, 1.5163, 1.5516};

double y_1[101]={0.0000, 0.0100, 0.0200, 0.0300, 0.0400, 0.0500, 0.0600,0.0700, 0.0800, 0.0900, 0.1000, 0.1100, 0.1200, 0.1300, 0.1400, 0.1500,0.1600, 0.1700, 0.1800, 0.1900, 0.2000, 0.2100, 0.2200, 0.2300, 0.2400,0.2500, 0.2600, 0.2700, 0.2800, 0.2900, 0.3000, 0.3100, 0.3200, 0.3300,0.3400, 0.3500, 0.3600, 0.3700, 0.3800, 0.3900, 0.4000, 0.4100, 0.4200,0.4300, 0.4400, 0.4500, 0.4600, 0.4700, 0.4800, 0.4900, 0.5000, 0.5100,0.5200, 0.5300, 0.5400, 0.5500, 0.5600, 0.5700, 0.5800, 0.5900, 0.6000,0.6100, 0.6200, 0.6300, 0.6400, 0.6500, 0.6600, 0.6700, 0.6800, 0.6900,0.7000, 0.7100, 0.7200, 0.7300, 0.7400, 0.7500, 0.7600, 0.7700, 0.7800,0.7900, 0.8000, 0.8100, 0.8200, 0.8300, 0.8400, 0.8500, 0.8600, 0.8700,0.8800, 0.8900, 0.9000, 0.9100, 0.9200, 0.9300, 0.9400, 0.9500, 0.9600,0.9700, 0.9800, 0.9900, 1.0000};

double x_2[101]={0.0008, 0.0100, 0.0253, 0.0376, 0.0422, 0.0483, 0.0545,0.0606, 0.0698, 0.0775, 0.0882, 0.0943, 0.0943, 0.0989, 0.1066, 0.1112,0.1174, 0.1204, 0.1281, 0.1388, 0.1450, 0.1511, 0.1557, 0.1603, 0.1680,0.1772, 0.1818, 0.1848, 0.1864, 0.1940, 0.2002, 0.2048, 0.2155, 0.2217,0.2293, 0.2355, 0.2447, 0.2493, 0.2539, 0.2600, 0.2661, 0.2692, 0.2753,0.2815, 0.2861, 0.3060, 0.3137, 0.3229, 0.3352, 0.3444, 0.3536, 0.3689,0.3735, 0.3873, 0.3950, 0.4027, 0.4103, 0.4165, 0.4272, 0.4395, 0.4640,0.4717, 0.4901, 0.5054, 0.5254, 0.5377, 0.5499, 0.5607, 0.5729, 0.5837,0.6036, 0.6144, 0.6282, 0.6481, 0.6727, 0.6972, 0.7202, 0.7340, 0.7509,0.7570, 0.7862, 0.8107, 0.8399, 0.8813, 0.8889, 0.9104, 0.9258, 0.9350,0.9472, 0.9610, 0.9810, 1.0101, 1.0285, 1.0822, 1.1114, 1.1451, 1.2019,1.2295, 1.2786, 1.3369, 1.4841};

double y_2[101]={0.0000, 0.0100, 0.0200, 0.0300, 0.0400, 0.0500, 0.0600,0.0700, 0.0800, 0.0900, 0.1000, 0.1100, 0.1200, 0.1300, 0.1400, 0.1500,0.1600, 0.1700, 0.1800, 0.1900, 0.2000, 0.2100, 0.2200, 0.2300, 0.2400,0.2500, 0.2600, 0.2700, 0.2800, 0.2900, 0.3000, 0.3100, 0.3200, 0.3300,0.3400, 0.3500, 0.3600, 0.3700, 0.3800, 0.3900, 0.4000, 0.4100, 0.4200,0.4300, 0.4400, 0.4500, 0.4600, 0.4700, 0.4800, 0.4900, 0.5000, 0.5100,0.5200, 0.5300, 0.5400, 0.5500, 0.5600, 0.5700, 0.5800, 0.5900, 0.6000,0.6100, 0.6200, 0.6300, 0.6400, 0.6500, 0.6600, 0.6700, 0.6800, 0.6900,0.7000, 0.7100, 0.7200, 0.7300, 0.7400, 0.7500, 0.7600, 0.7700, 0.7800,0.7900, 0.8000, 0.8100, 0.8200, 0.8300, 0.8400, 0.8500, 0.8600, 0.8700,0.8800, 0.8900, 0.9000, 0.9100, 0.9200, 0.9300, 0.9400, 0.9500, 0.9600,0.9700, 0.9800, 0.9900, 1.0000};

double x_3[101]={0.0008, 0.0100, 0.0161, 0.0238, 0.0284, 0.0330, 0.0391,0.0453, 0.0499, 0.0560, 0.0591, 0.0621, 0.0683, 0.0759, 0.0790, 0.0867,0.0913, 0.0943, 0.0989, 0.1035, 0.1097, 0.1127, 0.1158, 0.1235, 0.1281,0.1342, 0.1388, 0.1404, 0.1434, 0.1465, 0.1496, 0.1542, 0.1618, 0.1664,0.1695, 0.1726, 0.1772, 0.1802, 0.1894, 0.1940, 0.2033, 0.2063, 0.2125,0.2201, 0.2247, 0.2278, 0.2355, 0.2385, 0.2447, 0.2508, 0.2554, 0.2646,0.2723, 0.2800, 0.2830, 0.2953, 0.3014, 0.3106, 0.3198, 0.3244, 0.3275,0.3352, 0.3382, 0.3459, 0.3582, 0.3628, 0.3766, 0.3919, 0.4073, 0.4134,0.4241, 0.4395, 0.4518, 0.4640, 0.4794, 0.4993, 0.5239, 0.5315, 0.5545,0.5622, 0.5914, 0.6113, 0.6251, 0.6588, 0.6727, 0.6972, 0.7171, 0.7401,0.7693, 0.7908, 0.8076, 0.8260, 0.8736, 0.9027, 0.9426, 1.0025, 1.0623,1.1175, 1.1758, 1.2832, 1.3814};

double y_3[101]={0.0000, 0.0100, 0.0200, 0.0300, 0.0400, 0.0500, 0.0600,0.0700, 0.0800, 0.0900, 0.1000, 0.1100, 0.1200, 0.1300, 0.1400, 0.1500,0.1600, 0.1700, 0.1800, 0.1900, 0.2000, 0.2100, 0.2200, 0.2300, 0.2400,0.2500, 0.2600, 0.2700, 0.2800, 0.2900, 0.3000, 0.3100, 0.3200, 0.3300,0.3400, 0.3500, 0.3600, 0.3700, 0.3800, 0.3900, 0.4000, 0.4100, 0.4200,0.4300, 0.4400, 0.4500, 0.4600, 0.4700, 0.4800, 0.4900, 0.5000, 0.5100,0.5200, 0.5300, 0.5400, 0.5500, 0.5600, 0.5700, 0.5800, 0.5900, 0.6000,0.6100, 0.6200, 0.6300, 0.6400, 0.6500, 0.6600, 0.6700, 0.6800, 0.6900,0.7000, 0.7100, 0.7200, 0.7300, 0.7400, 0.7500, 0.7600, 0.7700, 0.7800,0.7900, 0.8000, 0.8100, 0.8200, 0.8300, 0.8400, 0.8500, 0.8600, 0.8700,0.8800, 0.8900, 0.9000, 0.9100, 0.9200, 0.9300, 0.9400, 0.9500, 0.9600,0.9700, 0.9800, 0.9900, 1.0000};

double x_4[101]={0.0023, 0.0100, 0.0115, 0.0161, 0.0192, 0.0253, 0.0284,0.0314, 0.0360, 0.0391, 0.0407, 0.0422, 0.0483, 0.0499, 0.0529, 0.0560,0.0591, 0.0652, 0.0683, 0.0713, 0.0744, 0.0775, 0.0790, 0.0821, 0.0836,0.0867, 0.0897, 0.0913, 0.0943, 0.0974, 0.0989, 0.1035, 0.1051, 0.1097,0.1112, 0.1143, 0.1158, 0.1189, 0.1220, 0.1266, 0.1312, 0.1327, 0.1373,0.1388, 0.1450, 0.1480, 0.1542, 0.1572, 0.1588, 0.1618, 0.1664, 0.1695,0.1756, 0.1787, 0.1864, 0.1894, 0, 1956, 0.2079, 0.2186, 0.2217, 0.2309,0.2355, 0.2493, 0.2585, 0.2646, 0.2738, 0.2800, 0.2876, 0.2938, 0.3076,0.3152, 0.3290, 0.3352, 0.3428, 0.3551, 0.3720, 0.3781, 0.3858, 0.3965,0.4134, 0.4226, 0.4334, 0.4487, 0.4702, 0.4901, 0.5147, 0.5315, 0.5622,0.5960, 0.6144, 0.6527, 0.6987, 0.7325, 0.8107, 0.8475, 0.9043, 0.9641,1.0009, 1.0822, 1.1466, 1.3752};

double y_4[101]={0.0000, 0.0100, 0.0200, 0.0300, 0.0400, 0.0500, 0.0600,0.0700, 0.0800, 0.0900, 0.1000, 0.1100, 0.1200, 0.1300, 0.1400, 0.1500,0.1600, 0.1700, 0.1800, 0.1900, 0.2000, 0.2100, 0.2200, 0.2300, 0.2400,0.2500, 0.2600, 0.2700, 0.2800, 0.2900, 0.3000, 0.3100, 0.3200, 0.3300,0.3400, 0.3500, 0.3600, 0.3700, 0.3800, 0.3900, 0.4000, 0.4100, 0.4200,0.4300, 0.4400, 0.4500, 0.4600, 0.4700, 0.4800, 0.4900, 0.5000, 0.5100,0.5200, 0.5300, 0.5400, 0.5500, 0.5600, 0.5700, 0.5800, 0.5900, 0.6000,0.6100, 0.6200, 0.6300, 0.6400, 0.6500, 0.6600, 0.6700, 0.6800, 0.6900,0.7000, 0.7100, 0.7200, 0.7300, 0.7400, 0.7500, 0.7600, 0.7700, 0.7800,0.7900, 0.8000, 0.8100, 0.8200, 0.8300, 0.8400, 0.8500, 0.8600, 0.8700,0.8800, 0.8900, 0.9000, 0.9100, 0.9200, 0.9300, 0.9400, 0.9500, 0.9600,0.9700, 0.9800, 0.9900, 1.0000};

double x_5[101]={0.0008, 0.0054, 0.0100, 0.0130, 0.0161, 0.0192, 0.0222,0.0238, 0.0268, 0.0268, 0.0299, 0.0314, 0.0345, 0.0360, 0.0391, 0.0407,0.0437, 0.0453, 0.0483, 0.0514, 0.0529, 0.0545, 0.0575, 0.0621, 0.0637,0.0652, 0.0667, 0.0683, 0.0729, 0.0759, 0.0790, 0.0805, 0.0851, 0.0867,0.0913, 0.0928, 0.0989, 0.1005, 0.1051, 0.1066, 0.1097, 0.1127, 0.1174,0.1204, 0.1235, 0.1266, 0, 1296, 0.1327, 0.1358, 0.1388, 0.1419, 0.1450,0.1496, 0.1542, 0.1572, 0.1618, 0, 1649, 0.1695, 0.1772, 0.1833, 0.1925,0.2002, 0.2033, 0.2109, 0.2201, 0.2247, 0.2324, 0.2355, 0.2431, 0.2508,0.2569, 0.2631, 0.2707, 0.2830, 0.2907, 0.3030, 0.3122, 0.3168, 0.3260,0.3398, 0.3505, 0.3597, 0.3659, 0.3735, 0.3919, 0.4119, 0.4211, 0.4364,0.4656, 0.4794, 0.4978, 0.5147, 0.5576, 0.6144, 0.6374, 0.6834, 0.7401,0.7724, 0.8537, 0.9963, 1.3154};

double y_5[101]={0.0000, 0.0100, 0.0200, 0.0300, 0.0400, 0.0500, 0.0600,0.0700, 0.0800, 0.0900, 0.1000, 0.1100, 0.1200, 0.1300, 0.1400, 0.1500,0.1600, 0.1700, 0.1800, 0.1900, 0.2000, 0.2100, 0.2200, 0.2300, 0.2400,0.2500, 0.2600, 0.2700, 0.2800, 0.2900, 0.3000, 0.3100, 0.3200, 0.3300,0.3400, 0.3500, 0.3600, 0.3700, 0.3800, 0.3900, 0.4000, 0.4100, 0.4200,0.4300, 0.4400, 0.4500, 0.4600, 0.4700, 0.4800, 0.4900, 0.5000, 0.5100,0.5200, 0.5300, 0.5400, 0.5500, 0.5600, 0.5700, 0.5800, 0.5900, 0.6000,0.6100, 0.6200, 0.6300, 0.6400, 0.6500, 0.6600, 0.6700, 0.6800, 0.6900,0.7000, 0.7100, 0.7200, 0.7300, 0.7400, 0.7500, 0.7600, 0.7700, 0.7800,0.7900, 0.8000, 0.8100, 0.8200, 0.8300, 0.8400, 0.8500, 0.8600, 0.8700,0.8800, 0.8900, 0.9000, 0.9100, 0.9200, 0.9300, 0.9400, 0.9500, 0.9600,0.9700, 0.9800, 0.9900, 1.0000};

double x_6[101]={0.0023, 0.0054, 0.0069, 0.0084, 0.0100, 0.0130, 0.0161,0.0176, 0.0192, 0.0207, 0.0238, 0.0238, 0.0253, 0.0284, 0.0284, 0.0314,0.0330, 0.0345, 0.0360, 0.0376, 0.0407, 0.0422, 0.0453, 0.0468, 0.0483,0.0499, 0.0529, 0.0545, 0.0575, 0.0575, 0.0621, 0.0621, 0.0637, 0.0652,0.0683, 0.0698, 0.0713, 0.0729, 0.0744, 0.0775, 0.0805, 0.0821, 0.0851,0.0867, 0.0913, 0.0943, 0.0989, 0.1020, 0.1051, 0.1097, 0.1158, 0.1189,0.1220, 0.1250, 0.1281, 0.1312, 0.1342, 0.1373, 0.1404, 0.1465, 0.1480,0.1511, 0.1572, 0.1618, 0.1664, 0.1726, 0.1756, 0.1802, 0.1864, 0.1925,0.2017, 0.2048, 0.2094, 0.2140, 0.2186, 0.2263, 0.2293, 0.2355, 0.2477,0.2539, 0.2569, 0.2615, 0.2723, 0.2938, 0.2984, 0.3106, 0.3413, 0.3597,0.3781, 0.3965, 0.4287, 0.4410, 0.4533, 0.4962, 0.5285, 0.5929, 0.6266,0.6987, 0.7816, 0.9488, 1.3108}:

double y_6[101]={0.0000, 0.0100, 0.0200, 0.0300, 0.0400, 0.0500, 0.0600,0.0700, 0.0800, 0.0900, 0.1000, 0.1100, 0.1200, 0.1300, 0.1400, 0.1500,0.1600, 0.1700, 0.1800, 0.1900, 0.2000, 0.2100, 0.2200, 0.2300, 0.2400,0.2500, 0.2600, 0.2700, 0.2800, 0.2900, 0.3000, 0.3100, 0.3200, 0.3300,0.3400, 0.3500, 0.3600, 0.3700, 0.3800, 0.3900, 0.4000, 0.4100, 0.4200,0.4300, 0.4400, 0.4500, 0.4600, 0.4700, 0.4800, 0.4900, 0.5000, 0.5100,0.5200, 0.5300, 0.5400, 0.5500, 0.5600, 0.5700, 0.5800, 0.5900, 0.6000,0.6100, 0.6200, 0.6300, 0.6400, 0.6500, 0.6600, 0.6700, 0.6800, 0.6900,0.7000, 0.7100, 0.7200, 0.7300, 0.7400, 0.7500, 0.7600, 0.7700, 0.7800,0.7900, 0.8000, 0.8100, 0.8200, 0.8300, 0.8400, 0.8500, 0.8600, 0.8700,0.8800, 0.8900, 0.9000, 0.9100, 0.9200, 0.9300, 0.9400, 0.9500, 0.9600,0.9700, 0.9800, 0.9900, 1.0000};

double x_7[101]={0.0008, 0.0038, 0.0054, 0.0084, 0.0084, 0.0100, 0.0100,0.0115, 0.0130, 0.0161, 0.0176, 0.0176, 0.0207, 0.0222, 0.0238, 0.0238,0.0253, 0.0268, 0.0284, 0.0299, 0.0314, 0.0314, 0.0330, 0.0345, 0.0360,0.0376, 0.0391, 0.0391, 0.0437, 0.0468, 0.0483, 0.0514, 0.0529, 0.0545,0.0560, 0.0591, 0.0606, 0.0621, 0.0652, 0.0667, 0.0683, 0.0698, 0.0713,0.0729, 0.0729, 0.0759, 0.0775, 0.0775, 0.0805, 0.0836, 0.0851, 0.0882,0.0913, 0.0959, 0.0959, 0.0989, 0, 1020, 0.1051, 0.1081, 0.1097, 0.1127,0.1158, 0.1204, 0.1250, 0.1342, 0.1373, 0.1404, 0.1465, 0.1496, 0.1557,0.1634, 0.1680, 0.1710, 0.1756, 0.1772, 0.1833, 0.1894, 0.1956, 0.2017,0.2109, 0.2201, 0.2263, 0.2355, 0.2447, 0.2585, 0.2646, 0.2769, 0.2846,0.2984, 0.3137, 0.3490, 0.3613, 0.3766, 0.4395, 0.4610, 0.4978, 0.5637,0.5929, 0.6834, 0.8322, 1.1006};

double y_7[101]={0.0000, 0.0100, 0.0200, 0.0300, 0.0400, 0.0500, 0.0600,0.0700, 0.0800, 0.0900, 0.1000, 0.1100, 0.1200, 0.1300, 0.1400, 0.1500,0.1600, 0.1700, 0.1800, 0.1900, 0.2000, 0.2100, 0.2200, 0.2300, 0.2400,0.2500. 0.2600, 0.2700, 0.2800, 0.2900, 0.3000, 0.3100, 0.3200, 0.3300,0.3400, 0.3500, 0.3600, 0.3700, 0.3800, 0.3900, 0.4000, 0.4100, 0.4200,0.4300, 0.4400, 0.4500, 0.4600, 0.4700, 0.4800, 0.4900, 0.5000, 0.5100,0.5200, 0.5300, 0.5400, 0.5500, 0.5600, 0.5700, 0.5800, 0.5900, 0.6000,0.6100, 0.6200, 0.6300, 0.6400, 0.6500, 0.6600, 0.6700, 0.6800, 0.6900,0.7000, 0.7100, 0.7200, 0.7300, 0.7400, 0.7500, 0.7600, 0.7700, 0.7800,0.7900, 0.8000, 0.8100, 0.8200, 0.8300, 0.8400, 0.8500, 0.8600, 0.8700,0.8800, 0.8900, 0.9000, 0.9100, 0.9200, 0.9300, 0.9400, 0.9500, 0.9600,0.9700, 0.9800, 0.9900, 1.0000}

The Abstract is provided to allow the reader to ascertain the nature andgist of the technical disclosure. It is submitted with the understandingthat it will not be used to limit or interpret the scope or meaning ofthe claims. The following claims are hereby incorporated into thedetailed description, with each claim standing on its own as a separateembodiment.

What is claimed is:
 1. An apparatus of a wireless communication deviceoperable to communicate channel state information in a wireless network,the apparatus comprising: memory; and processing circuitry coupled tothe memory, the processing circuitry arranged to: derive one or moreprincipal eigen beams from received Orthogonal Frequency DivisionMultiple Access (OFDMA) signals, the one or more principal eigen beamshaving a rank greater than or equal to one; derive quantized eigen beamsfrom the one or more principal eigen beams; select, in response to thequantized eigen beams, a subset of antenna ports from a plurality ofavailable antenna ports; condition at least one of a wideband channelquality indicator (CQI) or a subband CQI on the quantized eigen beams;and provide a bit pattern of the quantized eigen beams and at least oneof the wideband CQI or the subband CQI conditioned on the quantizedeigen beams for transmission by a transceiver circuitry via a ChannelState Information Reference Signal (CSI-RS) and using the selectedsubsets of antenna ports.
 2. The apparatus of claim 1, wherein theprocessing circuitry is further arranged to calculate, in response tothe quantized eigen beams, a plurality of phase values and a pluralityof amplitude values, each amplitude and phase value corresponding to arespective antenna port in the subset of available antenna ports, eachamplitude value corresponding to a signal amplification factor, eachphase value corresponding to a signal phase delay.
 3. The apparatus ofclaim 1, wherein the processing circuitry uses a Givens rotation toquantize Nc antenna ports for the one or more principal eigen beams,where Nc is a number of antenna ports on the apparatus.
 4. The apparatusof claim 3, wherein the processing circuitry further quantizes aprecoder of rank r into X phases, where X is a positive integer withvalue equal to 2*Σ_(k=0) ^(r)(Nc−k−1).
 5. The apparatus of claim 4,wherein: the processing circuitry evenly quantizes a first half of thephases to have Np bits per phase, where Np is a number of layers; theprocessing circuitry unevenly quantizes a second half of the phases tohave Ns bits per phase; and Np and Ns are positive integers.
 6. Theapparatus of claim 5, wherein the processing circuitry uses the firsthalf of the phases to rotate each element of the precoder from a complexnumber to a nonnegative real number; and wherein the processingcircuitry uses the second half of the phases to rotate the precoder toan identity matrix.
 7. The apparatus of claim 5, wherein the processingcircuitry quantizes each phase, of the first half of the phases, evenlyin the range between 0 and 2*pi; and wherein the processing circuitryquantizes each phase, of the first half of the phases, according to theequationD ₀=diag([e ^(jδ) ^(0,0) e ^(jδ) ^(1,0) e ^(jδ) ^(2,0) e ^(jδ) ^(3,0) e^(jδ) ^(4,0) e ^(jδ) ^(5,0) e ^(jδ) ^(6,0) 1]), wherein 0≤j≤1.
 8. Theapparatus of claim 5, wherein the processing circuitry quantizes eachphase, of the second half of the phases, in the range between 0 and 2*piusing a cumulative distribution function (CDF).
 9. The apparatus ofclaim 8, wherein the processing circuitry maps each phase, of the secondhalf of the phases, to the CDF; wherein the processing circuitry evenlyquantizes a phase probability in a range between 0 and 1 to form aquantized probability; wherein the processing circuitry maps thequantized probability using an inverse of the CDF to a quantized phase;and wherein the processing circuitry sequentially quantizes phases ofeach column of the CDF.
 10. The apparatus of claim 1, wherein theprocessing circuitry further quantizes a precoder of rank r into Xphases and X ratios, where X is a positive integer with value equal to2*Σ_(k=0) ^(r)(Nc−k−1), and where Nc is a number of antenna ports on theapparatus.
 11. The apparatus of claim 10, wherein the processingcircuitry further quantizes the ratios according to the followingequations of complex numbers: ${a_{2,0} = \begin{bmatrix}\alpha_{0,0} \\\alpha_{1,0}\end{bmatrix}},{b_{2,0} = \begin{bmatrix}\alpha_{2,0} \\\alpha_{3,0}\end{bmatrix}},\mspace{11mu}{{{{and}\mspace{14mu}\gamma_{2,0}} = \frac{{a_{2,0}}^{2} - {b_{2,0}}^{2}}{{a_{2,0}}^{2} + {b_{2,0}}^{2}}};}$${a_{2,1} = \begin{bmatrix}\alpha_{4,0} \\\alpha_{5,0}\end{bmatrix}},{b_{2,1} = \begin{bmatrix}\alpha_{6,0} \\\alpha_{7,0}\end{bmatrix}},\mspace{11mu}{{{{and}\mspace{14mu}\gamma_{2,1}} = \frac{{a_{2,1}}^{2} - {b_{2,1}}^{2}}{{a_{2,1}}^{2} + {b_{2,1}}^{2}}};}$${a_{1,0} = \alpha_{0,0}},{b_{1,0} = \alpha_{1,0}},\mspace{11mu}{{{{and}\mspace{14mu}\gamma_{1,0}} = \frac{{a_{1,0}}^{2} - {b_{1,0}}^{2}}{{a_{1,0}}^{2} + {b_{1,0}}^{2}}};}$${a_{1,1} = \alpha_{2,0}},{b_{1,1} = \alpha_{3,0}},\mspace{11mu}{{{{and}\mspace{14mu}\gamma_{1,1}} = \frac{{a_{1,1}}^{2} - {b_{1,1}}^{2}}{{a_{1,1}}^{2} + {b_{1,1}}^{2}}};}$${a_{1,2} = \alpha_{4,0}},{b_{1,2} = \alpha_{5,0}},\mspace{11mu}{{{{and}\mspace{14mu}\gamma_{1,2}} = \frac{{a_{1,2}}^{2} - {b_{1,2}}^{2}}{{a_{1,2}}^{2} + {b_{1,2}}^{2}}};\mspace{11mu}{and}}$${a_{1,3} = \alpha_{6,0}},{b_{1,3} = \alpha_{7,0}},\mspace{11mu}{{{and}\mspace{14mu}\gamma_{1,3}} = {\frac{{a_{1,3}}^{2} - {b_{1,3}}^{2}}{{a_{1,3}}^{2} + {b_{1,3}}^{2}}.}}$wherein a, b and y are complex numbers.
 12. The apparatus of claim 1,wherein the transceiver circuitry is arranged to: receive data sent froman antenna array of an evolved Node-B (eNB) using a precoder calculatedfrom the one or more principal eigen beams, wherein each received OFDMAsignal is transmitted with an independent beamforming pattern from theantenna array of the eNB.
 13. The apparatus of claim 1, wherein thewideband CQI and the subband CQI are transmitted to an evolved Node-B(eNB) in a wireless network.
 14. The apparatus of claim 1, wherein theprocessing circuitry is arranged to: derive the quantized eigen beamsfrom the one or more principal eigen beams using Givens rotation.
 15. Anapparatus of an evolved Node B (eNB), the apparatus comprising: memory;and processing circuitry coupled to the memory, the processing circuitryconfigured to: decode Channel State Information Reference Signal(CSI-RS) received from a user equipment (UE) to derive a bit pattern ofrecommended eigen beams and at least one of a wideband channel qualityindicator (CQI) or a subband CQI conditioned on the recommended eigenbeams; calculate a precoder from the bit pattern of the recommendedeigen beams; and encode a plurality of Orthogonal Frequency DivisionMultiple Access (OFDMA) signals with the bit pattern of the recommendedeigen beams for transmission to the UE using the precoder.
 16. Theapparatus of claim 15, wherein the processing circuitry is configuredto: encode each of the plurality of OFDMA signals for transmission tothe UE using an independent beamforming pattern from an antenna array ofthe eNB.
 17. A non-transitory computer-readable medium containinginstructions which, when executed by a processor, perform operations tocommunicate channel state information from a user equipment (UE) to anEnhanced Node B (eNB) in a wireless network, the operations to arrangethe UE to: derive one or more principal eigen beams from receivedOrthogonal Frequency Division Multiple Access (OFDMA) signals, the oneor more principal eigen beams having a rank greater than or equal toone; derive quantized eigen beams from the one or more principal eigenbeams; select, in response to the quantized eigen beams, a subset ofantenna ports from a plurality of available antenna ports on the eNB;condition at least one of a wideband channel quality indicator (CQI) ora subband CQI on the quantized eigen beams; and provide a bit pattern ofthe quantized eigen beams and at least one of the wideband CQI or thesubband CQI conditioned on the quantized eigen beams for transmission tothe eNB via a Channel State Information Reference Signal (CSI-RS) usingthe selected subset of antennas.
 18. The non-transitorycomputer-readable medium of claim 17, wherein the operations furtherarrange the UE to: quantize a precoder of rank r into X phases and Xratios, where X is a positive integer with value equal to 2*Σ_(k=0)^(r)(Nc−k−1), and where Nc is a number of available antenna ports on theUE.
 19. The non-transitory computer-readable medium of claim 17, whereinthe operations further arrange the UE to: receive data sent from anantenna array of the eNB using a precoder calculated from the principaleigen beams, wherein each received OFDMA signal is transmitted with anindependent beamforming pattern from the antenna array of the eNB.